In my previous blog post, I shared some pictures of the 3D printed parts I designed in Autodesk’s Fusion 360, for more info check out the blog post at – Continuous Servo Bot- 3D Printing. The idea when designing the 3D printed parts was to make them minimalistic so that they can be printed quickly in less than an hour. Basically the parts below with my printer and infill setting of 20% takes about 50 mins to print.

For the brain of the bot, I am using a Arduino Nano, and to power it up I am using a 2 cell Lipo battery. Also, let me know in the comments below if you would like to see a WiFi version of the bot, this would mean I can replace the Arduino nano with a Arduino MKR1000.

Now if you plan on replicating this project, and give the bot 'eyes, you will also have to 3D print the Ultrasonic sensor holder STL file as you see in the picture below. Here are the circuit connections to the Arduino Nano

left servo connected to pin# 5

right servo connected to pin# 6

Trigger pin of the Ultrasonic sensor connected pin# 9

Echo pin of the Ultrasonic sensor connected pin# 10

2 cell Lipo connected to the Vin pin on the Nano

And, here is the Arduino code to upload to the Nano using the Arduino IDE

When mounting the battery , use Velcro if possible instead of double sided sticky tape, so it is easy to change the weight distribution if required, this was pointed out by Andy in a comment on my previous blog post –

Looking good. The weight distribution is key so try and get the majority of the weight on the wheels rather than the skid as the marble can dig in on some surfaces. If you go too far the other way and the bot will pull a wheelie when accelerating.

And here is a picture of the bottom of the bot, which show the marble held at the back of 3D printed part.